Electrical circuit interrupting device

ABSTRACT

An electrical switch including a first switch contact mounted at a point spaced in front of a support, and a second switch contact mounted on the support for movement from an on-position in which it engages the first contact to an off-position in which it is spaced to the rear of the second contact. One of the switch contacts has a quenching chamber connected to it which surrounds the space between the first and second contacts until they are separated by a sufficient distance so that arcing no longer occurs. The mounting means for the second switch contact moves the second contact first in a linear direction away from the first contact and then in a pivotal direction back toward the support.

United States Patent [72] Inventors Erwin Reich] 'I'egernheim;

Gunter Sleklera, Regensburg; Helmut Klndler, Regensburg, all of, Germany[2| App]. No. 853,697 [22] Filed Aug. 28, I969 [45] Patented Aug. 31,I971 [73] Assignee Sachsenvverk Licht, und Kraft AktlengesellschaftMunich, Germany [54] ELECTRICAL CIRCUIT INTERRUPTING DEVICE IZ-CIaims, 5Drawing Figs. 52 us. c|..... zoo/144 R, 200/ 148 F [51] Int. Cl H0lh33/00 [50] Field of Search 200/146, 148.6,148 A, 148, 148.3, 144 R [56]References Cited UNITED STATES PATENTS 2,223,731 12/1940 Lingal 200/1462,272,717 2/1942 Ludwig et al. ZOO/I46 2,337,889 l2/l943 Harlow et al.ZOO/I48 (A) X FOREIGN PATENTS 552,068 3/1956 Italy 200/148 A PrimaryExaminer-Robert S. Macon Attorney-Spencer and Kaye ABSTRACT: Anelectrical switch including a first switch con-- tact mounted at a pointspaced in front of a support, and a second switch contact mounted on thesupport for movement from an on-position in which it engages the firstcontact to an off-position in which it is spaced to the rear of thesecond contact. One of the switch contacts has a quenching chamberconnected to it which surrounds the space between the first and secondcontacts until they are separated by a sufficient distance so thatarcing no longer occurs. The mounting means for the second switchcontact moves the second contact first in a linear direction away fromthe first contact and then in a pivotal direction back toward thesupport.

' PATENIEUAussI 19 1 13,602,667

- sutnlurz Erwin Reichl Giinter Sieki Helmut Kin r Y ATTORNEYS.

INVENTORS.

ELECTRICAL CIRCUIT INTERRUNG DEVICE BACKGROUND OF THE INVENTION Thisinvention relates to electrical switches for power circuits, and moreparticularly to a switch having tubular contacts actuated by a leversystem.

Most conventional switches for power circuits have pivoted knifelikeswitching members which are moved away from a contact for a sufiicientdistance such that sparking can not occur when the switch is in the ofiposition. Accordingly, the size of the switching cubicle or the enclosedmetal switch board is determined by the voltage of the system and thedistance by which the knife switches must be moved to prevent sparking.

A resulting drawback is that it is not possible'to reduce the size ofthe switching installations without creating safety hazards. Similarsize limitations exist for circuit breakers used for protecting againstpower surges and other overloads. In the cutoff position for either suchelectrical switches or circuit breakers there may be a considerablespace requirement since the switching blades may be rotated through 180from an onposition in which it is in contact with the associated switchconnection to an off-position in which it lies flat against the boardand extends in the opposite direction.

SUMMARY OF THE INVENTION Among the objects of the present invention isthe provision of electrical switches which may occupy relatively smallspace and, in which the space requirement for the switch contact is notsubstantially different in either the on or the off position.

Briefly stated, these and other objects of the invention are achieved byproviding a means for first moving the tubular switching contact awayfrom the associated electrical contact and then in a pivotal directionto the rear of this contact. One switch contact has a quenching chamberat one end for sur rounding the space between the contacts until theyare separated by a distance such that arcing can no longer occur. Thelinkage system for moving the tubular contact includes a member having acam surface and a bolt which is connected to a guide connected to thetubular contact.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view, partially incross section, of an electrical switch according to the presentinvention in its off-position.

FIG. 2 is a side view similar to FIG. I showing the switch of FIG. I inan intermediate position between its on and off-positions.

FIG. 3 is a side view similar to FIG. I showing the switch of FIG. I inits on-position.

FIG. 4 is a front view of the switch of FIG. 1, with the switch shown inits off-position.

FIG. 5 is a sectional view taken on the line 5-5 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,and particularly FIGS. 1-4, an electrical switch according to thepresent invention includes a support frame 1 formed by side members 50connected by cross members d2, as shown in FIG. 4, carrying insulators 2and 3. The upper insulator 2 carries a powerline connection t and astationary electrical contact 5. Stationary contact 5 includes aninsulating housing 27 of generally tubular shape and a centralelectrical contact 26 of cylindrical shape which is coaxial with housing27, and is electrically connected to the current carrying lineconnection 4 by a power lead 28. A sleeve 30 of insulating material islocated between the housing 27 and the contact 26.

The lower insulator 3 carries at its outer end a bracket 7 rigidlysupported by a second power line connection 6. Pivoted to the end ofbracket 7 is a housing 9 which is made of insulating material in theform of an elongated tube of generally rectangular cross section. A pin8 carried by bracket '7 is pivotally' connected to the lower end ofhousing 9. One of the lateral walls of housing 9 has a camming slot I6formed therein. A roller 31 (FIG. 3) rides in camming slot 16 and isrotatably mounted on a bolt 14 which is in turn connected to a lever I3.

The end of bolt M fits within a forked slide guide 17 which is fastenedto a movable electrical contact 12. Movable electrical contact llllincludes a lower tubular portion 32 of electrically conductive materialhaving an inner diameter of appropriate shape to engage with the fixedarc contact 26. At its upper end it includes a tubular portion Ml formedof insulating material. This material can be of a type which forms a gasunder the influence of the arc.

Portion MI is coaxial with the contact portion 32, and which serves toform a quenching chamber for quenching the arc formed when contact 26first separates from contact 32. A flexible current lead 26) connectscontact 32 and connection 6.

The electrical contact portion 32 could, if desired, be surrounded by asleeve of insulating material. The forked slide guide I7 is integralwith this sleeve and is preferably also made of insulating material.

The lever 13 which carries the bolt 114 at its free end is pivoted atits opposite end by a shaft 12 to the side members W of frame l. Thelever is formed of two links 360 and 36b, shown in FIG. 5, made of amaterial such as metal selected for its mechanical properties ratherthan its electrical properties. In order to provide electricalinsulation, lever I3 carries a troughlike member 18 having sidewalls 18awhich are secured to the lever links 360 and 36b, a bottom wall 18bwhich connects the two sidewalls, and an end wall 186, all of theportions of member 118 being of insulating material.

Trough 13 serves two purposes: In the off-position of the switch,thetrough receives the parts of the switch contact 11 to which apotential may be applied, and thus serves to insulate these parts eitherfrom the ground or from parts at a different electrical potential; inaddition it serves as an abutment for the switch contact III. A padding1.9 of elastic material is fixed to the bottom wall I8b near the endwall 18d. This serves to dampen mechanical shocks occurring as theswitch contact 11 moves into abutting position. The use of the flexiblecurrent lead 20 for making electrical connections between the contactIll and the line connection 6 prevents any current flow throughmechanical pivot joints, which ilow might cause charring. v

The rotation of lever I3 about its pivot 22 is caused by a rod 23 whichis connected to lever 13 by a pivot pin 25 at one of the ends of therod. The opposite end of rod 23 is pivoted by a pivot pin 24 to a rockerarm 22 which is fixed to a shaft 21. Shaft 21 is rotatably mounted inthe side members 40 of support I behind the insulator 3.

The shaft 21 could, of course, be rotated in any desired manner, as by amanuaily operated crank or a suitably controlled servomotor.

The dimensions of the lever transmission system are so selected thatshaft 2E. rotates through about as the switch contact ii is moved fromits off-position to its on position. By reference to FIG. 3 it will benoted that the maximum moment is exerted on lever 13 at the end of theswitch-on movement, for a fixed shaft rotation force. Thus greaterdriving forces are available as tubular contact 32 engages thestationary electrical contact 26. The lever force transmissionarrangement also serves to help lock the switch in the on position. Inthat case, as shown in FIG. 3, the drive shaft 21 and the pivot pins 24and 25 are in a common plane, and rocker arm 22 and connecting arm 23extend in a straight line so as to be in their dead center position.

The cam slot 16, previously described as being located in one of thewalls of the insulating housing 9, has, as shown in FIG. 3, an uppercurved portion 16a having a radius of curvature equal to the radialdistance between bolt 14 and shaft 12. At the lower end of this curvedportion the slot continues into a substantially straight portion 16b.When shaft 21 is first rotated in a counterclockwise direction from theoff position as shown in FIG. 1, bolt 14 is in the bottomof the straightportion 16b of slot 16. initially the bolt rotates housing 9 to anupright position as it moves in slot portion 1612.

After the housing 9 and the movable electrical contact 11 reach theupright position as shown in FIG. 2 further rotation of the shaft 21moves the bolt along the curved slot portion 16a. This lifts the movablecontact 11 within the housing 9. During this movement bolt 14 slideswithin the forked slide guide 17 and the quenching chamber portion ofcontact 11 first moves about the stationary contact 26 so as to containany arcing which occurs as the movable electrical contact portion 32approaches the fixed contact 26. Finally, near the end of the rotarymovement of shaft 21 the electrical contact portions 26 and 32 come intocontact with each other.

During the switching off process the action occurs in a reversesequence. First the electrical contact 32 is moved away from contact 26,then arcing occurs during the period when contact 26 is surrounded bythe quenching chamber portion 10. The dimensions of the quenchingchamber 10 are such that are current is completely interrupted by thetime the end of the chamber separates from the end of the upper contact26. Thereafter the holder 9 and the contact 1 1 move back toward thesupport 1.

It will be readily apparent that the structure of the present inventionpermits the construction of switches occupying space substantially lessthan that required for the usual prior art switches. Moreover, it ispossible to very easily maintain a voltage isolation for each switchfrom the front wall of the cabinets containing the switches or thecontrol panels and also between the electrical contacts of the switch. Afurther advantage is the relatively small amount of mass that has to bemoved as a result of the contacts being shortened to a fraction of theirconventional lengths. The voltage conducting width of each connectionterminal, or pole, is no greater than the width a of the connectingportions 4 and 6 as is shown in FIG. 4, the switch contacts themselvesbeing well insulated.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes andadaptations.

We claim:

1. An electrical circuit interrupting device, comprising in combination:

a. a support frame;

I). a first insulator mounted on said support frame at one end thereofand projecting therefrom;

c. a first electrical contact mounted on said first insulator at a pointspaced from said support frame;

d. a second insulator mounted on said support frame to project in thesame direction as said first insulator but spaced therefrom;

e. a housing member pivotally mounted on said second insulator at apoint spaced from said support frame;

f. a second electrical contact slidably mounted within said housingmember, said second electrical contact being of tubular shape;

g. a quenching chamber on said second electrical contact,

said quenching chamber being of tubular shape;

h. lever means pivotally connected to said support frame;

i. a bolt means mounted on said lever means;

j. connected means on said second electrical contact for engaging saidbolt; and

k. cam means on said housing member, whereby said housing member isinitially swingable from a position between said insulators to a secondposition where said first electrical contact and said second electricalcontact are in alignment, and whereby further swingable movement of saidlever means urges said electrical contacts to engagement.

2. The combination defined in claim 1, including roller means on saidbolt means engaging said cam means.

3. The combination defined in claim 1 wherein said bolt means islocatedon said lever means at a fixed distance from the lever pivot, andwherein said cam means includes a cam member having a surface which hasa radius of curvature equal to the radial distance of said bolt fromsaid lever pivot.

4. The combination defined in claim 3 wherein said cam member furtherhas a linear surface located at the end of said curved surface'foreffecting the pivotal movement of said housing member.

5. The combination defined inclaim 1 wherein said connecting means has afork shape formed of a pair of parallel members slidably engaging saidbolt means on opposite sides thereof.

6. The combination defined in claim 1 wherein said quenching chambermeans includes a tubular member connected at the end of said secondelectrical contact.

7. The combination defined in claim 1 wherein said member is ofinsulated material with said cam means being mounted on a wall of saidhousing member.

8. The combination defined in claim 1 wherein said lever means includesa pair of spaced substantially parallel links, and a trough-shapedconnecting member formed of insulating material, mounted between saidlinks, and wherein said cam means moves said housing member into saidtrough-shaped member when said housing member is in a position betweensaid first and second insulators to thereby insulate said secondelectrical contact from ground or from parts at a different electricalpotential. V

9. The combination defined in claim 1 wherein said lever means includesa shaft member rotatably mounted in said support frame. v

10. The combination defined in claim 9 wherein said lever means includesa rocker arm fixed to said shaft member for rotation therewith, a rodmember having a first joint pivotally connected to said rocker arm at apoint radially spaced from the axis of said shaft member, and furtherconnecting means connecting a second joint located on said rod at apoint spaced from said first joint to said links whereby when saidelectrical contacts are in engagement the axis of said shaft member, andsaid first and second joints on the rod member are in a common plane.

11. The combination defined in claim 1 wherein said housing member has alength less than the distance between its pivotal mounting point on saidsecond insulator and said support frame whereby said housing member andsaid second electrical contact can be moved by said lever means to aposition between said first and second insulators and said supportframe.

12. The combination defined in claim 1 including a flexible current leadelectrically connecting said second electrical contact and an associatedcurrent carrying line.

1. An electrical circuit interrupting device, comprising in combination:a. a support frame; b. a first insulator mounted on said support frameat one end thereof and projecting therefrom; c. a first electricalcontact mounted on said first insulator at a point spaced from saidsupporT frame; d. a second insulator mounted on said support frame toproject in the same direction as said first insulator but spacedtherefrom; e. a housing member pivotally mounted on said secondinsulator at a point spaced from said support frame; f. a secondelectrical contact slidably mounted within said housing member, saidsecond electrical contact being of tubular shape; g. a quenching chamberon said second electrical contact, said quenching chamber being oftubular shape; h. lever means pivotally connected to said support frame;i. a bolt means mounted on said lever means; j. connected means on saidsecond electrical contact for engaging said bolt; and k. cam means onsaid housing member, whereby said housing member is initially swingablefrom a position between said insulators to a second position where saidfirst electrical contact and said second electrical contact are inalignment, and whereby further swingable movement of said lever meansurges said electrical contacts to engagement.
 2. The combination definedin claim 1, including roller means on said bolt means engaging said cammeans.
 3. The combination defined in claim 1 wherein said bolt means islocated on said lever means at a fixed distance from the lever pivot,and wherein said cam means includes a cam member having a surface whichhas a radius of curvature equal to the radial distance of said bolt fromsaid lever pivot.
 4. The combination defined in claim 3 wherein said cammember further has a linear surface located at the end of said curvedsurface for effecting the pivotal movement of said housing member. 5.The combination defined in claim 1 wherein said connecting means has afork shape formed of a pair of parallel members slidably engaging saidbolt means on opposite sides thereof.
 6. The combination defined inclaim 1 wherein said quenching chamber means includes a tubular memberconnected at the end of said second electrical contact.
 7. Thecombination defined in claim 1 wherein said member is of insulatedmaterial with said cam means being mounted on a wall of said housingmember.
 8. The combination defined in claim 1 wherein said lever meansincludes a pair of spaced substantially parallel links, and atrough-shaped connecting member formed of insulating material mountedbetween said links, and wherein said cam means moves said housing memberinto said trough-shaped member when said housing member is in a positionbetween said first and second insulators to thereby insulate said secondelectrical contact from ground or from parts at a different electricalpotential.
 9. The combination defined in claim 1 wherein said levermeans includes a shaft member rotatably mounted in said support frame.10. The combination defined in claim 9 wherein said lever means includesa rocker arm fixed to said shaft member for rotation therewith, a rodmember having a first joint pivotally connected to said rocker arm at apoint radially spaced from the axis of said shaft member, and furtherconnecting means connecting a second joint located on said rod at apoint spaced from said first joint to said links whereby when saidelectrical contacts are in engagement the axis of said shaft member, andsaid first and second joints on the rod member are in a common plane.11. The combination defined in claim 1 wherein said housing member has alength less than the distance between its pivotal mounting point on saidsecond insulator and said support frame whereby said housing member andsaid second electrical contact can be moved by said lever means to aposition between said first and second insulators and said supportframe.
 12. The combination defined in claim 1 including a flexiblecurrent lead electrically connecting said second electrical contact andan associated current carrying line.